1. Field of the Invention
The present invention is in the field of fluid flow couplings. More particularly, the present invention relates to those types of fluid flow couplings which include a first, or male, part and a second, or female, part, which when these parts are connected to one another effect fluid flow communication therebetween. When the coupling parts are so connected they may be used to effect fluid flow connection between a fluid-holding vessel and a fluid flow conduit, for example. When the coupling parts are disconnected from one another they mutually or individually reseal so that fluid is not lost either from the conduit or from the vessel. Additionally, this type of coupling desirably has a minimal retention volume of fluid which is not sealed either in the conduit or in the vessel upon disconnection of the coupling parts, and which is thus released into or exposed to ambient conditions.
2. Related Technology
Conventional coupling structures are known in accord with U.S. Pat. Nos. 4,375,864 (Re 32,354); and 4,445,551. In the first instance, the coupling structure includes an adaptor connected to a storage vessel and defining an opening sealed by a movable plug. A tubular probe is receivable sealingly in the adaptor to remove the plug from sealing engagement with the adaptor and to carry this plug inwardly of the vessel as the probe moves inwardly of the adaptor to open fluid communication between the vessel and a conduit communicating with the probe. Upon withdrawal of the probe from the adaptor, the plug is carried back into sealing engagement with the adaptor. The probe carries a quantity of retained fluid, but communication of fluid from the conduit to the ambient is prevented by a check valve internal to the probe.
With the coupling structure disclosed by the '551 patent, a service coupling portion includes a plug valve member which is movable between a first position in which this plug valve member closes communication with a storage vessel, and a second position in which a pair of lateral outlets moves inwardly of the storage vessel to permit fluid communication between this vessel and the outer portion of the service coupling. A connector member portion defines a through axial passage and is sealingly engageable with the plug valve to lock therewith and then to move the plug valve member axially from its first position to its second position. When the connector member portion is withdrawn from the service coupling, the plug valve is first drawn from its second position to its first position to close the vessel, and then the connector member portion unlocks from the plug valve to allow completion of the withdrawal of the connector member portion from the service coupling. With this coupling structure, the service coupling portion and connector member portion retain a considerable volume of fluid which is either lost to or exposed to the ambient when the portions of the coupling structure are disconnected. Also, flow of fluid from the conduit communicating with the connector member portion and to the ambient is not prevented when the coupling structure is disconnected.
Other conventional coupling structures are known in accord with U.S. Pat. Nos. 4,948,014; and 5,095,962. The first of these two coupling structures includes a spout member connecting to a storage vessel, such as a fluid-filled bag. A socket member is engageable with the spout member to connect the vessel to a conduit in fluid flow communication. The spout is a tubular body with an internal resiliently-biased tubular valving member which is axially biased at a valving surface thereon into sealing relation with a valve seat defined by an annular end wall of the spout member. Similarly, the socket member is a cup-shaped member receivable sealingly over the spout and including a poppet valve member axially biased resiliently into sealing engagement with a valve seat disposed at the closed end of the cup-shaped socket member. The socket member connects in fluid flow relationship with a conduit. A stem of the poppet valve member extends into the open center of the cup-shaped socket. When closed, the valve structure of the socket closes communication of ambient with the conduit.
When the socket and spout of the '014 coupling structure are engaged with one another, the stem of the poppet valve engages an end wall of the tubular member to force both of these members out of sealing engagement with their respective valve seats. Thus, the vessel is communicated with the conduit of the socket member. Upon disconnection of the socket member and the spout member, only a relatively small volume of fluid is retained to be exposed to or lost to ambient. However, with a coupling structure according to the '014 patent, both the socket and the spout members are complex and relatively costly components to manufacture. Further, the complexity of these components increases the manufacturing costs for this coupling structure by increasing both the inspection costs and scrap rates for this coupling structure.
A coupling structure according to the '962 patent includes a tubular spout attached to and in fluid communication with a fluid filled vessel, such as a bag. This spout portion includes a plug member sealing disposed for axial movement between a first position closing fluid communication between the vessel and an outer portion of the spout member, and a second position opening this fluid communication.
A valve member is slidably engageable axially into sealing relation with the spout at the plug member of this spout portion. The valve member communicates with a conduit and includes an internal plug valve. The plug valve internally resiliently engages a valve seat of the valve member to close communication of fluid from the conduit. Engagement of the valve member with the plug member of the spout opens the plug valve of the valve member. Further axial movement of the valve member into the spout member unseats the plug member and moves it to its second position so that the vessel is communicated with the conduit.
When the valve member and spout member of the '962 coupling are axially disengaged from one another, only a very small volume of fluid is retained outwardly of the valve member and spout. This retention volume of fluid is very small because the valve member defines a domed end surface, and the plug member has a matching contoured end wall closely fitting to the valve member. Lateral ports of the plug member are themselves of small volume, and the passage leading to the plug valve member of the valve member itself is small and is mostly filled by the plug valve member itself when this plug valve moves to its closed position. Consequently, this coupling structure has only a small volume of fluid which is retained therein upon disconnection of the component parts of the coupling structure.
Generally, coupling structures of the type discussed above are employed to connect a fluid-filled bag to a receiver for the fluid. The fluid-filled bag may contain a food product. For example, the fluid may be syrup of the type which is mixed with carbonated water to make soft drinks. The receiver for the fluid in this case would be a soft drink dispenser. Thus, it is seen that the fluid dispensed is a food product which could be contaminated by exposure to bacteria and soil in the environment. Also, when the parts of such coupling structures are disconnected, loss of such a food-product fluid to the ambient results in unsanitary conditions around the storage vessel. This may be the case at the food preparation and dispensing facilities of a restaurant or hotel, for example. Thus, the importance of such coupling structures having a small, or preferably zero, retained volume of fluid upon disconnection of the coupling parts is easily appreciated.
However, many food products which are of fluid, semi-fluid, or paste-like consistency, such as salad dressings and other condiments, for example, also contain pieces or chunks of various foods and spices. These pieces might be chopped pickle, chopped onion, pepper, or chunks of such food items as cheese or other food materials, as well as particles of such things as spices, for example. Other fluid, semi-fluid, and paste-like food products may contain other kinds and other consistencies of chunks or particulate of various food ingredients and spices. These chunks and particulate present a special problem and difficulty when it is desired to dispense such food products in bulk from a vessel, such as a fluid-filled bag, by use of the conventional couplings. That is, the chunks and particulate of food may lodge in and jam the various parts of the conventional coupling structures. The valving features of these conventional coupling structures also may not close securely when the fluid contains chunks and particulate of food. The result of this failure to function properly with the conventional coupling structures may be the leakage or contamination and spoilage of food product, as was discussed above. Also, if either of the coupling portions fails to close properly when the coupling is disconnected, the loss of food product may create unsanitary conditions and attract insects and vermin to the food preparation area of a hotel or restaurant, for example.